 //封装一个获取请求参数的方法
 function getQueryString() {
  var searchStr = location.search;    //获取请求参数      '?a=1&b=2&c=3'
  var newStr = searchStr.substr(1)
  var arr = newStr.split('&');        //['a=1','b=2','c=3']
  var newArr = [];
  var obj = {};
  for (var i = 0; i < arr.length; i++) {
    newArr = arr[i].split('=');        //['a','1'],['b','2'],['c','3']
    obj[newArr[0]] = newArr[1];
  }
  return obj;
}